Art of refrigeration



Jan. 23, 1934. H. SLOAN ET AL 1,944,472

ART OF REFRIGERATION Filed Sept. 22, 1930 2 Sheets-Sheet l M 9! MA TToRNEY.

Jan. 23, 1934. H SLQAN ET AL 1,944,472

ART OF REFRIGERAT ION Filed Sept. 22, 1930 2 Sheets-Sheet 2 h jill/1111,11

Patented Jan. 23, 1934 ART F REFRIGERATION Harry Sloan, Ernst S. H. Baars, and Charles G. Bach, Milwaukee, Wis., assignors to The Vilter Manufacturing Company, Milwaukee, Wis., a corporation of Wisconsin Application September 22, 1930 Serial No. 483,526

10 Claims. (Cl. (i2- 115) This invention relates in general to improve- To provide improved cooling apparatus for sysments in the art of refrigeration, and relates tems wherein the refrigeration requirements are more specifically to improvements in the convariable throughout the freezing period. struction of refrigerating apparatus and in the To provide improved /eans for defrosting the mode of operating refrigerating systems especialcooling coils of a refrige ator without materially 60 ly for the purpose of obtaining quick freezing of interfering with the normal operation thereof, the product treated. and without undesirably raising the temperature Generally stated, an object of the invention is within the cooling zone. to provide improvements in the art of refrigera- To provide improved means for facilitating retion whereby more efcient and economical coolfrigeration of objects of various shapes and 65 ing may be effected under various conditions of forms.

operation. To provide an i proved mode of maintaining Some of the more specific objects of the invenobjects in frozen condition for a maximum period tion may be enumerated as follows: of time.

l5 To provide an improved quick freezing or low These and other objects and advantages will 70 temperature refrigeration system which is simappear from the following detailed description. ple in construction and eiiicient in operation. A clear conception of embodiments of the va- To provide an improved low temperature rerious novel features and of the improved mode frigerator which is operable with greater econof constructing and of operating refrigerating 2O omy in power consumption than has heretofore apparatus built in accordance with the invention, 75 been possible in such devices. may be had by referring to the drawings accom- To provide an improved system of refrigerapanying and forming a part of this specification, tion which is capable of maintaining extremely in which like reference characters designate the low freezing temperatures of approximately 60 same or similar parts in the several views:

to '70 Fahrenheit below zero, within the cooling Fig. 1 is a diagram of an improved quick freez- 80 coils of the system. ing refrigeration system embodying the inven- To provide an improved quick freezing refrigtion, and of improved means for defrosting the eration system which may be readily operated in cooling coils of the system;

conjunction with existing refrigerating systems. Fig. 2 is an enlarged section through one of To provide an improved refrigerating system the special fittings employed in the improved 85 of the direct expansion type, wherein the evapquick freezing system; v orating surface is utilized to its fullest extent, Fig. 3 is a transverse vertical section through thus insuring more efficient operation of the sysa typical cooling room especially adapted for use tem. I in connection with the quick freezing refrigera- To provide improved instrumentalities for furtion system;

nishing a proper supply of liquid refrigerant at Fig. 4 is a perspective View of an improved suiciently high pressure to the liquid distributform of material supporting racks showing the ing headers of a refrigerating system, so as to same assembled for use in supporting relatively permit satisfactory regulation of the flow of relarge objects; and

frigerant from the headers. Fig.- 5 is a similar perspective View of several 95- To provide improved means for maintainingI of the improved racks showing the same assemthe entire evaporating surfaces of a refrigerating bled for use in connection with relatively at system supplied with an abundant quantity of liqobjects. uid refrigerant. The improved quick freezing refrigeration sys- To provide a low temperature refrigerating tem specifically illustrated in diagrammatic form 10Q system in which a compressor of relatively small in Fig. 1 of the drawings, comprises in general a capacity may be effectively utilized, thereby reprimary or ordinary refrigerating unit, and a ducing to a minimum the power consumption. secondary or low temperature refrigerating unit To provide improved means for removing oil adapted to receive its supply of liquid refrigerant and water from the uent refrigerant employed from a relatively low temperature portion of the 105 in arefrigerating system. primary refrigerating unit, the secondary unit To provide improved emergency devices for also being adapted to return the said refrigerant maintaining a refrigerating system in operation in gaseous condition to the primary unit at a upon failure of a portion of the system to functemperature corresponding to that of the source tion properly. v of gaseous refrigerant supply in said primary unit. 110

The primary or ordinary unit includes a high pressure compressor 13 having an inlet pipe 53 communicating with the gas collecting chamber of a high pressure accumulator 16, the compressor also having a discharge pipe 37 directed into the inlet end of a condenser 14, and into a defrosting connection 35 having a control valve 36 therein which is normally closed. A cooling water supply pan 54 is adapted to deliver cooling liquid such as water over the tubes of the condenser 14 to cool the gas discharged from the compressor 13 and finally condense it to a liquid which then flows from the condenser 14 to the receiver 15 through a header and connection 68. The outlet of the receiver l5 communicates with a pipe 55 having a pressure regulating and reducing valve 56 therein, the pipe 55 being adapted to deliver liquid refrigerant into the lower portion of the supply of liquid refrigerant within the accumulator 16. A pipe 47 communicates with the pipe at the high pressure side of the regulating valve 56, this pipe 47 having a control valve 62 therein and serving to conduct liquid refrigerant from the receiver 15 to an oil separator and cooler 41, the function of which will be later described. Another pipe 31 having a control valve 57 therein, is adapted to conduct liquid refrigerant at relatively high pressure from the receiver 15 to the inlet or supply pipe 4S of the secondary s vstem, for purposes which will be later explained.

The entrained gas contained winthin the liquid refrigerant delivered into the lower portion of the accumulator 16 through the pipe 55, bubbles upwardly through the refrigerant in the accumulator and eventually mixes with the gas in the collecting chamber at the upper end of the accumulator, from which the compressor 13 receives its supply. A liquid refrigerant withdrawal pipe 58 which is adapted for interchangeable connection with the supply pipe 48 of the secondary unit, either through a circulating pump 30 or through a valve controlled by-pass 43, also communicates with the accumulator 16 below the level of the liquid therein. and a refrigerant return pipe 46 leading from the separator and cooler 41, communicates with the upper end of the accumulator 16 above said liquid level. The lower portion of the accumulator 16 additionally communicates through a relatively large connection 44 with the lower part of the high temperature evaporator 17. the upper part of which communicates through a relatively large return connection 45 with the gas collecting chamber at the upper end of the accumulator 16. The evaporator 17 is of usual construction, being provided with the ordinary means for transferring heat from the brine to the refrigerant which passes through the evaporator 17 from the inlet connection 44 to the outlet connection 45.

The secondary or low temperature unit includes a low pressure compressor 11 of relatively small capacity, having an inlet pipe 59 communicating with the upper gas collecting chamber of a low pressure accumulator 19, the compressor also having a delivery pipe 60 directed into a discharge gas cooler 26, the delivery pipe 61 of which communicates with the separator and cooler 41. The separator and cooler 41 serves to reduce the temperature of the gaseous refrigerant delivered through the pipe 61, to that of the gases in the collecting chamber at the upper end of the accumulator 16, before the gaseous refrigerant is delivered to the return pipe 46. This result is accomplished by utilizing refrigerant from the receiver 15 and passing the same through the pipe 47 and valve 62 into the cooler 41 and causing the same to intermingle with the gaseous refrigerant passing from the cooler 26 through the cooler 41. The secondary refrigerating unit, moreover, has one or more evaporating coils 12, each of which receives its supply of liquid refrigerant from two headers 27, 21 and delivers gas and surplus liquid refrigerant to a suction header 63 past a fiow control valve 64. The first supply header 27 normally receives liquid refrigerant at relatively low temperature from the lower portion of the accumulator 16, through the pipes 58, 48, the latter of which is provided with shutoff valves 65, 66 and is adapted to deliver the low temperature refrigerant past control valves 18 and through ejector fittings 39 to the individual coils 12. The supply header 27 is, however, also adapted to receive liquid refrigerant at relatively high pressure, direct from the receiver 15 past the valve 57 and through the supply pipes 31, 48. The second supply header 21 normally receives liquid refrigerant from the low pressure receiver 19 through a circulating pump 20 and through the pipe 29 past a shut-off valve 38, and is adapted to deliver refrigerant past regulating valves 22 into the ejector fittings 39.

Each of the ejector fittings 39, the details of which are shown in Fig. 2, is so constructed that the liquid refrigerant delivered thereto from the pipe 48 under relatively high pressure, will iiow at high velocity across the annular gap which communicates directly with the supply header 21 containing liquid refrigerant at low pressure. The high velocity jet thus formed ejects liquid refrigerant from the header 21, and the mixture is delivered as a spray or in partially vaporized condition into the evaporators, and is deposited over the entire heat transfer surfaces of the coils 12, instead of being deposited only at the lower part of the pipes thus wetting only a small part of their inner surfaces. A valve controlled bypass 40 is also provided between the pipes 29, 48 for permitting delivery of liquid refrigerant from the accumulator 19 directly into the header 27 through the supply pipe 48. It is desirable that the liquid refrigerant be admitted vto the upper vend of the coils 12, as indicated in Fig. 1, in order to permit free evaporation of the downwardly advancing refrigerant, as well as to permit ready drainage of the coils.

The suction header 63 communicates through a pipe 28 with the gas collecting chamber of the accumulator 19. and this collecting chamber also communicates through the pipe 59 with the suction side of the compressor 11. The lower portion of the accumulator 19 has an oil separating trap 67 associated therewith, this trap being in communication with an oil drum 23 past a valve 25. The upper portion of the drum 23 is communicable through a valve 24 with the gas collecting chamber of the accumulator 19 and has a blow-off valve 42 associated with the lower portion thereof. By opening the valves 24, 25, the accumulated oil may be drained from the trap 67 into the drum 23, whereupon the valves 24, 25 g may be closed and the valve 42 opened to effect removal of the oil from the drum 23 by virtue of the expansion of the entrapped expansible refrigerant within the upper portion of the drum 23.

While the defrosting connection 35 may be utilized occasionally to admit high pressure gas at relatively high temperature to the coils 12, by opening the valve 36 and closing the valves 18,

38 and simultaneously retaining the valves 221 open, this method of completely defrosting the dimensions.

evaporator of the secondary unit, should only be utilized at relatively rare intervals, as for instance semi-annually. In addition to complete defrostation it is desirable, in order to maintain the system in most effective operating condition, to

` additionally defrost the coils 12 at frequent intervals and without interfering with the normal operation of the unit. This may be accomplished with the aid of the defrosting device shown 1n Fig. 1, which comprises a compressed air header 32, flexible hoses 33 communicating with the header 32, and valve controlled nozzles 34 for suddenly releasing compressed air against the surfaces of the coils 12 in the form of jets. The jets thus delivered against the coils serve to remove loose frost crystals from the coils 12, and the sudden expansion of the compressed air upon release thereof from the nozzles 34, produces a cooling effect and avoids undesirable heating of the coils 12 and of the cooling rooms 68.

Although the objects treated are of variable form and especially variable thickness, it is desirable to expose all portions of these objects to the cooling atmosphere and to provide a supporting structure which may be quickly adjusted to support a maximum number of the objects regardless of their shape, within a cooling room 68 of fixed In order to accomplish this result, special supporting racks shown in detail in Figs. 4 and 5 are provided. Each of these racks comprises longitudinally extending slats 49 and transverse intermediate supports 5U of rectangular cross-section. By piling the slats 49 and supports 50 as specifically shown in Fig. 4, relatively thick objects such as hams 51 may be piled upon the upper slats and between the successive layers of slats. By piling the slats 49 and supports 50 as shown in Fig. 5, relatively flat objects such as bacon sides 52 may be piled upon the upper slats and between the successive layers of slats. By tipping the intermediate supports 50 on their sides, the successive layers of slats 49 may be brought even closer together, thereby providing an extremely flexible supporting structure which is capable of supporting a maximum number of objects of various shapes within a given space. The entire structure remains within the cooling room 68, and the adjustment for the purpose of accommodating objects of various sizes and shapes may be quickly effected.

During normal operation of the refrigerating system specifically illustrated in Fig. 1, the compressor 13 of the primary unit is operated to withdraw gas through the pipe 53 from the accumulator 16 and to expel highly compressed gaseous refrigerant, usually ammonia, through the discharge pipe 37 to the condenser 14. In passing through the condenser 14, this highly compressed gas having relatively high initial temperature is cooled and simultaneously condensed by the cooling fluid delivered from the tray 54 and the relatively cool liquid refrigerant is delivered to the receiver 15. When the valve 57 is closed, the refrigerant from the receiver l5 is discharged through the pressure reducing valve 55 into the accumulator 16 and entrained gases are expelled upwardly through the liquid refrigerant in this accumulator and mingle with the gases collected at the upper end of the accumulator to await return to the compressor 13 with other gases discharged into this collecting chamber. Some of the liquid refrigerant passes from the accumulator 16 through the connection 44 to the evaporator 17, wherein the refrigerant is gasified and is eventually returned through the connection 45 to the gas collecting chamber in the upper end of the accumulator 16. If the pressure within the accumulator 16 is sufficiently high, the pump 30 is not being operated and the valve in the by-pass 43 is open, the valve 65 in the pipe 48 also being open. Liquid refrigerant then passes from the accumulator 16 through the pipe 58, by-pass 43 and pipe 48 to the header 27, the valve 66 also being open. From the header 27 the liquid refrigerant at relatively low temperature but at relatively high pressure, is delivered through the regulating valves 18 and ejector fittings 39 to the evaporator coils 12.

Simultaneously with this delivery of liquid refrigerant through the ejector fittings 39, additional liquid refrigerant is delivered from the header 21 through the ejector fittings, as previously explained, this additional refrigerant being forced through the pipe 29 and open valve 38 by means of the pump 20 communicating with the low pressure accumulator 19. An abundant supply of liquid refrigerant is therefore insured in each of the coils 12, and the ejector fittings 39 serve to spray the liquid ammonia thus admitted, into the coils 12 and thus insure proper coating of the heat transferring surfaces with refrigerant. The gases and surplus refrigerant delivered from the coils 12 passes through the valves 64 into the suction header 63 from which the mixture is delivered into the low pressure accumulator 19, The gases which collect in the upper portion of the accumulator 19 are withdrawn through the pipe 59 by the booster compressor 11, and are discharged by this compressor into the ammonia discharge gas cooler 26 from which they are subsequently discharged, through the pipe 6l, cooler 4l and pipe 46 to the'pressure accumulator 16 of the primary unit.

It the pressure within the accumulator is insufficient to force the liquid refrigerant through the pipe 58, by-pass 43, and pipe 48, to the coils l2, then the valve in the by-pass 43 may be closed and the emergency pump 30 may be placed in operation to withdraw the refrigerant from the accumulator 16 and to positively force the same through the header 27 and ejector fittings 39to the coils 12. It may also be desirable to utilize the liquid refrigerant directly from the receiver 15 in the secondary unit, and this may be done by opening the valve 57 in the pipe line 3l, and by closing the valve 65 in the pipe line 48. Under certain conditions, as when the low pressure accumulator becomes over supplied with liquid, it may be desirable to inject the excess liquid into the pipe 48 in advance of the ejector fittings 39. This may be done by adjusting the regulating valves 22 and opening the valve in the by-pass 40, to produce an increased pressure in the pipe 29 so that the excess liquid refrigerant will be forced into the pipe 48 and subsequently will pass through the header 27 and the ejector fittings 39. The operation of the cooler 41, oil expelling drum 23 and of the defrosting device, will be readily apparent from the foregoing description.

It will be apparent that the improved system provide". a h'ghly economical association of elements for producing quick freezing of materials. By virtue of the fact that the secondary refrigerating unit utilizes refrigerant derived from a relatively low temperature portion of the primary the secondary unit to perform the desired function, and the booster compressor 11 of the secondary unit may be of relatively small capacity and hence utilizes comparatively little power. The improved system abounds with safety devices whereby the secondary unit may be maintained in operating condition even if the primary unit should fail, and the various by-passes, pumps and auxiliary connections permit an operator to obtain practically any desired condition of operation of the secondary unit.4 The improved ejector fittings not only msi/1re an` abundant supply of refrigerantl for the coils l2, but also produce effective distribution of the refrigerant within the coils, and the defrosting devices and improved supporting racks also enhance the effectiveness of the unit to a maximum and permit eiicient treatment of the materials which are to be frozen. It should be moreover understood that the diagrammatic illustration of hand valves, is not to be considered as a limitation, since it is also contemplated tg utilize automatic valves wherever desirable.

It should be understood that it is not desired to limit this invention to the exact details of construction and to the preci'se mode of operating refrigerating systems, herein shown and described, for various modifications within the scope of the appended claims may occur to persons skilled in the art.

It is claimed and desired to secure by Letters Patent:

l. In combination, a primary refrigerating unit including a high pressure accumulator, a secondary refrigerating unit comprising an evaporator the inlet of which is adapted to receive refrigerant from a relatively low temperature portion of said h'gh prezsure accumulator, a low pressure accumulator communicating with the discharge of said evaporator, and means far delivering additional refrigerant from said low pressure accumulator to said inlet.

, 2. In combination, a high pressure accumulator, a low pressure evaporator, a low pressure accumulator communicating with the d'scharge of said evaporator, means for supplying refrigerant at relatively low temperature from said high pressure accumulator to the inlet of said evaporator, and means for supplying additional refrigerant from said low pressure accumulator to said first mentioned supply means.

3. In combination, an evaporator, a primary refrigerating unit for supplying a quantity of vhigh pressure refrigerant to said evaporator, a

low pressure accumulator for receiving liquid and gaseous refrigerant from said evaporator, a compressor for returning the gaseous portion of said refrigerant to said primary unit, and means for returning the liquid portion of said refrigerant to said evaporator.

4. In combination, an evaporator, a primary refrigerating unit comprising a receiver and a high pressure accumulator, means forestablishing a pressure difference in said receiver and said accumulator, and means for. eifecting interchangeable delivery of refrigerant from said receiver or from said accumulator to said evaporator.

5. In combination, a 10W temperature evaporator, a high pressure accumulator, means for conducting liquid refrigerant from a low temperature portion of said accumulator to said evaporator, a by-pass in said conducting means for normally effecting direct delivery of refrigerant through said conducting means by the higher pressure existing in said accumulator, and a pump for positively urging refrigerant thro h3,

said conducting means when said pressure is 1nsufficient.

6. In combination, a primary refrigerating unit including a high pressure accumulator and a high pressure compressor, a secondary refrigerating unit comprising a low pressure evaporator and a low pressure accumulator, means for normally delivering refrigerant from said high pressure accumulator to said evaporator and from said evaporator to said low pressure accumulator, and means for interchangeably delivering refrigerant from said compressor directly to said evaporator.

7. In combination, a primary refrigerating unit and a secondary refrigerating unit, each of said units comprising an evaportor, an accumulator, a compressor, and a receiver, means for conducting refrigerant from the accumulator of said primary unit to the evaporator of said secondary unit, and means for conducting refrigerant from the receiver of said secondary unit to the receiver of said primary unit.

8. In combination, primary and secondary refrigerating units each comprising an evaporator, an accumulator, a compressor, and a receiver, means for conducting refrigerant from the accumulator of said primary unit to the evaporator of said secondary unit, means for conducting refrigerant from the accumulator of said secondary unit to the compressor of said secondary unit, and means including the receiver of said secondary unit for conducting refrigerant from the compressor of said secondary unit to the accumulator of said primary unit.

9. In combination, primary and secondary refrigerating units each comprising an evaporator, an accumulator, a compressor, and a receiver, means for conducting refrigerant from the accumulator of said primary unit to the evaporator of said secondary unit, means for conducting refrigerant from the evaporator of said secondary unit through the accumulator and compressor and receiver of said unit to the accumulator of said primary unit, and means for conducting refrigerant from the accumulator of said primary unit to the evaporator and to the compressor of said unit.

10. In combination, primary and secondary refrigerating units each comprising an evaporator, an accumulator, a compressor, and a receiver, means for conducting refrigerant from the accumulator of said primary unit to the evaporator of said secondary unit, means for conducting refrigerant from the evaporator of said secondary unit through the accumulator and compressor and receiver of said unit to the accumulator of said primary unit, and means for conducting refrigerant from the compressor of said primary unit to the evaporator of said secondary unit.

HARRY SLOAN. ERNST S. H. BAARS. CHARLES G. BACH. 

